Reference Guide

Border Gateway Protocol | 217
Change BGP timers
Use either or both of the following commands in the CONFIGURATION ROUTER BGP mode to
configure BGP timers.
Use the
show config command in CONFIGURATION ROUTER BGP mode or the show running-config
bgp
command in EXEC Privilege mode to view non-default values.
Timer values configured with the
neighbor timers command override the timer values configured with the
timers bgp command.
When two neighbors, configured with different
keepalive and holdtime values, negotiate for new values,
the resulting values will be as follows:
• the lower of the
holdtime values is the new holdtime value, and
• whichever is the lower value; one-third of the new
holdtime value, or the configured keepalive value is
the new
keepalive value.
BGP neighbor soft-reconfiguration
Changing routing policies typically requires a reset of BGP sessions (the TCP connection) for the policies
to take effect. Such resets cause undue interruption to traffic due to hard reset of the BGP cache and the
time it takes to re-establish the session. BGP soft reconfig allows for policies to be applied to a session
without clearing the BGP Session. Soft-reconfig can be done on a per-neighbor basis and can either be
inbound or outbound.
BGP Soft Reconfiguration clears the policies without resetting the TCP connection.
Command Syntax Command Mode Purpose
neighbors {ip-address |
peer-group-name} timers
keepalive holdtime
CONFIG-ROUTER-BGP Configure timer values for a BGP neighbor or peer group.
• keepalive range: 1 to 65535. Time interval, in
seconds, between keepalive messages sent to the
neighbor routers. (Default: 60 seconds)
• holdtime range: 3 to 65536. Time interval, in seconds,
between the last keepalive message and declaring the
router dead. (Default: 180 seconds)
timers bgp keepalive holdtime CONFIG-ROUTER-BGP Configure timer values for all neighbors.
• keepalive range: 1 to 65535. Time interval, in
seconds, between keepalive messages sent to the
neighbor routers. (Default: 60 seconds)
• holdtime range: 3 to 65536. Time interval, in seconds,
between the last keepalive message and declaring the
router dead. (Default: 180 seconds)